System and Method for Bottom Coating Food Products

ABSTRACT

A product conveying and coating system includes at least first and second, sequentially arranged conveyor belts, with at least the second conveyor belt being a solid belt. Interposed in a gap between the first and second belts is a dispenser head of a coating manifold. The dispenser head spans a gap between upper surface portions of the first and second conveyor belts, with an elongated side wall outlet portion of the dispenser head being exposed, in a downstream direction of the conveyor unit, to the upper surface of the second conveyor belt. The system provides for dispensing of coating material directly onto the second, solid conveyor belt and enrobing at least bottom and partial side portions of food products upon the solid belt. Provisions are made for scraping from the solid belt, removing from the food products and recycling excess coating material.

FIELD OF THE INVENTION

The invention pertains to the art of coating food products and, morespecifically, to a system and method of coating bottom portions of foodproducts conveyed upon a solid belt.

BACKGROUND OF THE INVENTION

In the manufacturing of certain food products, it is sometimes desiredto provide a surface coating on the food products. For instance, topicalcoatings are quite common on a wide range of food products. The overallcoating process can significantly vary, particularly depending on thecoating material being employed and the food product surfaces to becoated. For instance, in the case of topical coatings, whether inparticulate or liquid form, it is common to provide a feed hopper orother dispenser above the food product as the product moves along aconveyor. In such an arrangement, the conveyor belt is generally formedof interconnected metal wires or links which enables most of the excesscoating material to fall or flow through the conveyor belt and collectedfor reuse. If it is desired to coat the bottom and even sides of a foodproduct, the conveyor belt can be directed into a container of thecoating material, essentially dipping the food product and mesh conveyorbelt in the coating material. In the art, this type of coating systemwhich enables coating of multiple surfaces of a food product is oftenreferred to as an enrober.

Known enrobers are considered to be quite expensive and complicated. Inaddition, in the food industry, the conveyors must be cleaned at regularintervals, which can be important for various reasons includingallergins. At least in the case of liquid coating enrobers, cleaning thelinks of the conveyor is extremely difficult and time consuming. By wayof example, in the range of twenty to thirty-five hours of man-time isoften required to clean an open mesh conveyor of an enrober system usedto apply chocolate to the bottom of chewy grain bars. Obviously, thisrepresents a significant amount of downtime for a production line.

SUMMARY OF THE INVENTION

The invention is directed to a system and method for enrobing at leastbottom and partial side portions of food products by utilizing aconveyor unit employing a solid belt at a coating station. Morespecifically, the invention provides for a product conveying systemincluding at least first and second, sequentially arranged conveyorbelts, with at least the second conveyor belt being constituted by asolid belt. Interposed in a gap between the first and second belts is adispenser head of a coating manifold. An upper surface of the secondconveyor belt is arranged in a plane just below a plane of an uppersurface of the first conveyor belt such that the dispenser head spansthe gap, with an elongated outlet portion of the dispenser head beingexposed, in a downstream direction of the system, to an upper surface ofthe second conveyor belt.

During operation, the manifold receives a liquid coating material anddispenses the coating material directly onto a predetermined percentageof the overall width of the second, solid belt while spaced foodproducts are directed from the first belt into the coating material onthe second belt. In accordance with an aspect of the invention, thecoating material is thick so as to not ready flow off the belt, therebyavoiding the need for any lateral containment structure on the solidbelt. With this arrangement, the coating material coats the bottom orlowermost side of the food product, as well as extending up and coatingside portions of the food product to a degree dependent upon the foodproduct being coated and the coating thickness or height applied to thesolid belt. Downstream of the dispenser head, the coated food product isremoved from the solid belt and the excess coating material is scrapedfrom the belt, collected, filtered and recycled back to the manifold.

In accordance with a particular embodiment of the invention, the coatingmaterial is thick, melted chocolate which is applied onto the solid beltwith a low pressure drop (e.g., less than 0.1 psig) across thehorizontal portion of the head and a higher pressure drop (e.g.,preferably in the range of 2-30 psig and, more preferably, 7-12 psig)across the vertical portion of the dispenser head to provide a uniformlayer thickness across the belt. The layer thickness depends on thedesired coating weight and is preferably about 6-9 mm for bottom coatingchewy grain bars and 2-5 mm for bottom coating of crunchy baked bars.Layer thickness is primarily varied by how much coating is applied tothe belt. Upon reaching a downstream end of the second belt, the coatedbars are automatically transferred onto a third conveyor belt which isalso solid and constitutes a cooling or chill belt, establishing apredetermined cooling temperature and residence time. Still, theinvention has applicability to a wide range of coatings and products,basically coating materials which can be heated and cooled to alterviscous characteristics thereof and food products which can be sheetedand conveyed. In any case, additional objects, features and advantagesof the invention will become more readily apparent from the followingdetailed description when taken in conjunction with the drawings whereinlike reference numerals refer to corresponding parts in the severalviews.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a food product coating and conveyingsystem according to an embodiment of the invention.

FIG. 2 is an enlarged perspective view of a portion of the system ofFIG. 1.

FIG. 3 is an enlarged view of a corner section of a tap-down roller unitemployed in connection with an aspect of the invention.

FIG. 4 is a perspective view of a terminal end of one conveyor sectionprovided in the system of FIG. 1.

FIG. 5 is a perspective view detailing another portion of the system ofFIG. 1.

DETAILED DESCRIPTION OF INVENTION

With initial reference to FIG. 1, a coating system constructed inaccordance with the present invention is generally indicated at 2.Coating system 2 incorporates a transfer station 6 including a firstconveyor unit 9 employing a first conveyor belt 12 shown as an endless,solid belt. In the position illustrated, conveyor belt 12 has a firstlongitudinal end 16 which extends about a roller 17 and leads to adownstream, second longitudinal end 18 which is also supported by aroller (not shown). Between first and second longitudinal ends 16 and 18is established an upper surface 21 of conveyor belt 12. Stemming fromsecond longitudinal end 18 is a down-turned portion 27 which extendsabout a drive roller 29 of a drive unit 32. At this point, it should benoted that drive roller 29 can be rotatably driven in various ways topropel conveyor belt 12. For instance, drive unit 32 can itselfconstitute an electric, hydraulic or other motor or, as in theillustrated embodiment, drive unit 32 can include a pulley 34 which isadapted to be driven by a further drive belt/motor drive mechanism (notshown). In any case, from drive roller 29, conveyor belt 12 has anupturned portion leading back to first longitudinal end 16. At thispoint, it should be apparent that the drawings presented here showsimplified conveyor arrangements for reference purposes only. Therefore,it should be understood that idler pulleys, tracking systems, take-upadjustment mechanisms and the like as commonly known in the art wouldalso be employed.

As will become more fully evident below, the present invention can beused in coating bottom and partial side portions of various products. Inone particular embodiment, coating system 2 is used in coat foodproducts 45 in the form of chewy grain bars, each having a bottomsurface 47, a front side surface 48, a rear side surface 49, lateralside surfaces 50 and 51, and a top surface 52. As shown, the previouslyprepared food products 45 have been deposited on upper surface 21 inrows and columns for transport by conveyor belt 12 from transfer station6 to a downstream coating station 55. Coating station 55 includes asecond conveyor unit 59 employing a second conveyor belt 63 having, inthe position illustrated, a first longitudinal end 66 supported by aroller 67 and a second longitudinal end 68 supported by a roller 69,with conveyor belt 63 establishing an upper surface 73 between first andsecond longitudinal ends 66 and 68. From upper surface 73, conveyor belt63 leads to a down-turned portion 76 extending around a drive roller 79of a drive unit 82, which may include a pulley 84 such as for a commondrive with drive unit 32, and an upturned portion 88 leading back tofirst longitudinal end 66.

For reasons which will be detailed more fully detailed below, it isimportant in accordance with the present invention that second conveyorbelt 63 is constituted by a solid conveyor belt, without any associatedopen mesh metal wires or links. In the embodiment shown, conveyor belt63 is formed entirely from a polymeric material, such as a polyesterbase provided with a polyurethane topcoat. That is, in order to notdepart from the invention, conveyor belt 63 must be solid, at leastacross a majority of the lateral dimension or width of conveyor belt 63.However, prior to further detailing this important aspect of theinvention, FIG. 1 also illustrates a cooling station 105 as part ofcoating system 2. As shown, cooling station 105 includes a frame 107supporting a third conveyor unit 110. Third conveyor unit 110 includes athird conveyor belt 113 shown having a first longitudinal end 116.Conveyor belt 113 is also shown to include an upper surface 123, areturn portion 126 extending about a guide roller 129 and a drive roller132 of a drive unit 135 having a pulley 137, and an upturned portion 140leading back to first longitudinal end 116. In order to establish adesired cooling function, cooling station 105 includes at least onechiller unit, such as indicated at 144, for cooling conveyor belt 113.In general, chiller unit 144 can take various forms, including employingconduction and/or convection cooling arrangements, with one preferredembodiment employing a chip plate cooler provided directly belowconveyor belt 113.

As best shown in FIG. 2, a vertical and longitudinal gap 151 isestablished between second longitudinal end 18 of first conveyor belt 12and first longitudinal end 66 of second conveyor belt 63. Interposed ingap 151 is a coating unit 153. More specifically, coating unit 153includes a manifold 157, having an input port 160, and an upstandingdispenser head 164. As clearly illustrated, it is dispenser head 164which projects into gap 151, with dispenser head 164 including anuppermost wall 169, an upstream side wall 170 and a downstream side wall171. In downstream side wall 171 and effectively extending across amajority of the lateral dimension or width of second conveyor belt 63 isat least one elongated dispensing opening or outlet 175 for dispensing acoating material 180 onto upper surface 73. More specifically, uppersurface 21 of first conveyor belt 12 is located in a plane above a planeestablished by upper surface 73 of second conveyor belt 63. Therefore,upper surface 73 is just below upper surface 21. On the other hand,uppermost wall 169 of dispenser head 164 is substantially flush withupper surface 21, while dispensing opening 175 has a lowermost edge (notseparately labeled) which is substantially coplanar with upper surface73, and an uppermost edge (also not labeled). With this arrangement,dispenser head 164 spans gap 151, with elongated outlet opening 175 ofdispenser head 164 being exposed, in a downstream direction of conveyorunit 9, to upper surface 73 of second conveyor belt 63 such that coatingmaterial 180 having a predetermined thickness (height) can be directlydeposited upon upper surface 73 of second conveyor belt 63 from aposition between first and second conveyor belts 12 and 63.

Prior to describing the overall operation of coating system 2, furtherstructure associated with the present invention will now be described inconnection with the illustrated embodiment. Initially, as shown in FIGS.1 and 3, coating system 2 can employ a tap-down or presser unit 188 forforcing food products 45 into coating material 180 upon second conveyorbelt 63. In the embodiment shown, presser unit 188 includes a pair ofside support brackets 191 and 192 which support a transverse shaft 194.Adjustably secured to shaft 194 is a lock collar 196 which defines astop surface 198. Presser unit 188 also includes a sleeve member 203extending about and rotatably supported by shaft 194, with sleeve member203 defining an abutment 206 aligned with stop surface 198. In addition,at spaced locations along shaft 194, presser unit 188 includes radialflanges 210, which extend from and are fixed to sleeve member 203 forrotation relative to shaft 194, and support rings 214 fixed to radialflanges 210. Each support ring 214 adjustably receives a respectivesupport rod 224, 225. Support rods 224 and 225 terminate in supportplates 228 and 229 which rotatably support a roller 233 having an outersheath 236. With this arrangement, sheath 236 engages the top surface 52of each food product 45 as second conveyor belt 63 is driven, therebyforcing the food products 45 to be partially immersed in coatingmaterial 180. The engagement of abutment 206 with stop surface 198limits the degree to which roller 233 can shift downward. Althoughroller 233 could be biased in this direction, it has been found that themere weight of this structure provides sufficient force for thisfunction. The vertical distance between roller 233 and upper surface 73of second conveyor belt 63 can be readily adjusted by securing lockcollar 196 to shaft 194 at a select location, such as with a set screw(not shown). Roller 233 can be freely, rotatably supported by supportplates 228 and 229, but roller 233 can also be positively driven torotate in unison with the movement of second conveyor belt 63, such asby employing a self-contained drive motor (not shown) within thestructure of roller 233.

FIGS. 1 and 4 illustrate the inclusion of a hopper 253 used to holdcoating material 180. More specifically, as best illustrated in FIG. 4,hopper 253 is shown to be supported by legs 256-259 (not depicted inFIG. 1 for clarity of the drawing) and includes an outlet port 262.Hopper 253 is positioned below upper surface 73 of second conveyor belt63 and has associated therewith a scraper device 265 including a blademember 268 having an edge 270 which engages inturned portion 176 ofsecond conveyor belt 63. With this arrangement, scraper device 265 islocated at a position spaced from second longitudinal end 68 and belowupper surface 73 of second conveyor belt 63. At this location, theexcess coating material 180 is scraped from second conveyor belt 63 andcollected in hopper 253, enabling the coating material 180 to be pumpedthrough outlet port 262, filtered and recycled back to manifold 157through additional pumping and filtering equipment (not shown).

FIGS. 1 and 5 will now be referenced in describing a spinner device 276also incorporated into coating system 2. As shown, spinner device 276includes a spinner bar 280 which is rotatably supported by a supportblock 284 at one end and a support plate 287 at another end. A drivemotor 290 is employed to rotate spinner bar 280. With this overallarrangement, the food products 45 deposited on first conveyor belt 12,which actually can be made of solid or mesh construction, aretransferred above uppermost wall 169 of dispenser head 164 onto coatingmaterial 180 already deposited upon upper surface 73 of second, solidconveyor belt 63. Although coating material 180 and the thickness(height) thereof can vary in accordance with the invention, oneembodiment employs about a 8-9 mm layer of thick chocolate having amolasses-like consistency being delivered through an approximately 7.5cm delivery pipe (not shown) connected to inlet port 160 of manifold 157at a temperature in the range of 35-46° C. (about 95-115° F.).Importantly, the solid construction of conveyor belt 73 is such thatcoating material 180 will not flow through upper surface 73. At the sametime, coating material 180 is thick, i.e., has a high viscosity, suchthat coating material 180 must be pumped for dispensing and will notflow laterally off of upper surface 73. For dispensing the coatingmaterial 180, upstanding dispenser head 164 is designed such that thereis a very low pressure drop across the width, but rather the majority ofthe pressure drop occurs over the height.

In accordance with a particular embodiment of the invention, the coatingmaterial is thick, melted chocolate which is applied onto the solid beltwith a low pressure drop (e.g., less than 0.1 psig) across thehorizontal portion (not separately labeled) of dispenser head 164 and ahigher pressure drop (e.g., preferably in the range of 2-30 psig and,more preferably, 7-12 psig) across the vertical portion (not separatelylabeled) of dispenser head 164. This assures an even flow, with foodproducts 45 becoming partially immersed in coating material 180 suchthat coating material 180 will become enrobed on at least bottom surface47 and portions of front, rear and side surfaces 48-51. The layerthickness depends on the desired coating weight and is preferably 6-9 mmfor bottom coating chewy grain bars and 2-5 mm for bottom coating ofcrunchy baked bars. At the same time, presser unit 188 can furtherassure that an appropriate tap-down force is applied on food products 45for proper coating. Once reaching second longitudinal end 68, the coatedfood products 298 are transferred onto third conveyor belt 113 ofcooling station 105, while excess coating material 180 is delivered intohopper 253 in conjunction with scraper device 265. Any tailing of thecoating material 180 associated with the transfer to cooling station 105is avoided by the presence of spinner device 276.

The length of first conveyor unit 9 will depend on the overallmanufacturing configuration. On the other hand, the length of secondconveyor unit 59 can actually be quite short, such as less than 2meters, along with a preferably commensurate width. The length of thirdconveyor unit 110 will depend on the time need to cool and furthersolidify coating material 180. In the case of chocolate, a rather longcooling period is typically needed, such as about a 3 minute residencetime. With this in mind, this length can be from 12-25 meters, but canbe advantageously reduced to about 3 meters utilizing certain conveyormaterial and a flat, aluminum plate cooling system. To this end, a thin,high heat transfer material, such as TEFLON, having a thickness in theorder of about 0.025 cm (10/1000 of an inch) can be advantageouslyemployed as the conveyor material such that this overall chillingarrangement can reduce the cooling time to approximately 40 seconds.

Although described with reference to exemplary embodiments of theinvention, it should be readily understood that various changes and/ormodifications can be made to the invention without departing from thespirit thereof. For instance, other than applying chocolate, variousother coating materials which can be heated and cooled could beemployed, including yogurt, marshmallow, fruit and cheese. In addition,other food products which can be sheeted and conveyed could be coated,including candy, dough, cereal, cookies and ice cream. Most importantly,it has been found that completely avoiding mesh metal conveyor materialsbut rather utilizing the solid and small length (less surface area)conveyor belt as discussed above for the coating operation enables thecleaning time to be significantly reduced, basically from aboutthirty-five hours to about four hours, thereby representing a majorefficiency enhancement.

I/we claim:
 1. A method of coating bottom and partial side portions of afood product comprising: directing the food product in a longitudinaldirection along a first conveyor belt which is spaced from a second,solid conveyor belt by a gap; dispensing a coating material onto andlaterally across a portion of the second, solid conveyor belt fromwithin the gap; transferring the food product from upon the firstconveyor belt onto the second, solid conveyor belt wherein the foodproduct becomes partially immersed in the coating material to establisha coated food product; and removing the coated food product from thesecond, solid conveyor belt.
 2. The method of claim 1, wherein the gapconstitutes a longitudinal gap and the coating material is dispensedfrom at least one side wall opening provided in a dispenser headprojecting vertically into the longitudinal gap.
 3. The method of claim2, further comprising: pumping the coating material to the dispenserhead through a manifold.
 4. The method of claim 3, further comprising:collecting excess coating material from the second, solid conveyor beltand recycling the excess coating material to the manifold.
 5. The methodof claim 4, wherein collecting the excess coating material includesscraping the excess coating material from the second, solid conveyorbelt.
 6. The method of claim 1, further comprising: forcibly pressingthe food product into the coating material upon the second, solidconveyor belt.
 7. The method of claim 1, wherein delivering the coatingmaterial across a portion of the second, solid conveyor belt constitutesdelivering the coating material across a majority of the second, solidconveyor belt.
 8. The method of claim 7, wherein the coating material isthick such that, upon dispensing the coating material onto and laterallyacross the majority of the second, solid conveyor belt, the coatingmaterial does not flow laterally off the second, solid conveyor belt. 9.The method of claim 1, wherein removing the coated food product from thesecond, solid conveyor belt includes transferring the coated foodproduct to a third conveyor belt which is longitudinally aligned withthe second, solid conveyor belt, said method further comprising chillingthe coated food product on the third conveyor belt.
 10. The method ofclaim 1, wherein the food product constitutes a chewy grain bar and thecoating material constitutes chocolate.
 11. A system for coating bottomand partial side portions of a food product comprising: a first conveyorbelt, said first conveyor belt being configured to deliver a foodproduct in a longitudinal direction; a second, solid conveyor beltaligned with and longitudinally spaced from the first conveyor belt by alongitudinal gap; and a dispenser head positioned within the gap andincluding at least one dispensing opening exposed to an upper surface ofthe second, solid conveyor belt, wherein coating material is configuredto be dispensed from the dispenser head onto and laterally across aportion of the second, solid conveyor belt from within the longitudinalgap such that food product delivered upon the first conveyor belt can betransferred onto the second, solid conveyor belt and become partiallyimmersed in the coating material in order to establish a coated foodproduct.
 12. The system according to claim 11, wherein the dispenserhead includes an uppermost wall, an upstream side wall and a downstreamside wall, said at least one dispensing opening being provided in thedownstream side wall for dispensing of the coating material.
 13. Thesystem according to claim 12, wherein the uppermost wall of thedispenser head is substantially flush with an upper surface of the firstconveyor belt.
 14. The system according to claim 12, further comprisinga manifold for the coating material, said dispenser head projecting fromthe manifold.
 15. The system according to claim 14, wherein the second,solid conveyor belt includes a first longitudinal end juxtapose the gapand a second longitudinal end, said system further comprising a scraperdevice for removing excess coating material from the second, solidconveyor belt and a hopper for collecting the excess coating material,said scraper device being located at a position spaced from the secondlongitudinal end and below the upper surface of the second, solidconveyor belt.
 16. The system according to claim 11, further comprising:a presser unit mounted above the upper surface of the second, solidconveyor belt for forcibly pressing the food product into the coatingmaterial upon the second, solid conveyor belt.
 17. The system accordingto claim 16, wherein the presser unit includes a roller extendinglaterally across the second, solid conveyor belt and means for adjustinga height of the roller above the upper surface of the second, solidconveyor belt.
 18. The system according to claim 11, wherein the second,solid conveyor belt includes a first longitudinal end juxtapose the gapand a second longitudinal end, said system further comprising a spinnerbar provided at the second longitudinal end for removing excess coatingmaterial from the food product.
 19. The system according to claim 11,further comprising: a third conveyor belt which is longitudinallyaligned with the second, solid conveyor belt downstream of the firstconveyor belt, said third conveyor belt constituting a chiller belt forchilling the coated food product on the third conveyor belt.
 20. Thesystem according to claim 19, wherein each of the first and third beltsare also constituted by solid belts such that the system is void of anyopen mesh belts.